In a drop-forging press comprising an automatic workpiece conveyor, it is common to transport the workpieces from one work station to the next work station by means of a lifting mechanism. Different types or models of lifting mechanisms are known in the prior art for the transporting of workpieces, such as a lifting mechanism comprising two parallel lifters from DE 37 21 694 [U.S. Pat. No. 4,966,274], each provided with grabs in order to be able to grip the workpieces between the lifters, lift them from the die, and transport them to the next work station. Another model of lifting mechanism incorporates only one lifter provided with a grab.
In operation with the automatic workpiece conveyor using the above mentioned lifting mechanisms within the work space of a drop-forging press, there is no stopping between forging of parts, but instead, the workpiece conveyor runs continuously. Forging is usually done with every other forging operation, i.e. only every second closing of the die is effective on a workpiece during the automatic process.
The blowing-out and/or spraying of the dies, which is indispensable in forming machines producing workpieces in a continually repeated manner, can be carried out in this case only if the dies are clear and no press stroke is currently being performed. Known electrically, pneumatically, or hydraulically controlled spray arms, which are provided with spray nozzles, can therefore only move into the work space or extend into the work space if the press ram assumes its idle position in the upper dead center. This means that a significant part of the blow-out and/or spray time that is already short is lost due to control and monitoring times. A spray arm apparatus operated in such a manner is known from DE 32 30 095 [U.S. Pat. No. 4,520,643].
DE 38 44 262 [U.S. Pat. No. 4,840,052] discloses mobile spray nozzle devices that operate in a timed manner on actuation of the press ram in order to move spray nozzles into the space between the upper and lower die parts that are separated. This apparatus utilizing a carriage that is displaceable via a hydraulic or pneumatic actuator, or a cam mechanism driven by means of the drive shaft of a moving apparatus, requires an actuation time that is too long, of 1.5 to 2 seconds on average for the performance of one work cycle, i.e. movement through one forward stroke and one backward stroke for inserting the spray nozzle apparatus between the die parts and its subsequent removal.